Multiple stroke pliers



April 5, 1955 M. D. LAZAR MULTIPLE STROKE PLIERS 2 Sheets-Sheet 1 Filed Nov. 14, 1952 ilnlllllllllll'llll INVENTOR fl/lzbizaelflba afi JIBY W 6 ATTORNEY April 1955 M. D. LAZAR 2,705,432

MULTIPLE STROKE PLIERS Filed Nov. 14, 1952 2 Sheets-Sheet 2 ll/am,

m INVENTOR 1:12. MZWF M ATI'O NErF United States Patent MULTIPLE STROKE PLIERS Michael D. Lazar, New York, N. Y., assignor to Burndy Engineering Company, Inc., a corporation of New York Application November 14, 1952, Serial No. 320,451

Claims. (Cl. 81-46) When using pliers for crimping electrical connectors it is desirable to provide long handles to reduce operator fatigue. Long handles or levers require less input force to do the required work and provide a high mechanical advantage. Lengthening the handles, however, introduces other undesirable factors. The longer the handle, the wider is the spread between the ends of the handles, and this makes the long-levered pliers unlikely for use in confined quarters, more difficult to use, and induces early operator fatigue.

The principal object of my invention, therefore, comprises the provision of pliers having a large mechanical 1advantage, with a small span at the ends of the opened evers.

Further objects are to provide a short-span long-lever pliers, the jaws of which open wider than can be expected of ordinary pliers of similar size, to provide pliers with a positive and quick means of properly locating and hold ing the connector in the jaws; to provide pliers which apply sufficient force to not only indent the connector to the metal conductor, but also to simultaneously close the insulating shroud of the connector about the conductor insulation; to provide pliers which require a full stroke before opening to insure a uniform and perfect indenting crimp with each connection made, to provide pliers with jaws that are adjustable with respect to their operating mechanism; and to provide pliers having the foregoing characteristics which are relatively light in weight and which do not require close tolerances in manufacture that are difiicult to obtain in mass production.

I accomplish these and other objects and obtain my new results as will be apparent from the device described in the following specification, particularly pointed out in the claims, and illustrated in the accompanying drawing, in which:

Fig. 1 is a top view of my improved pliers partly in section.

Fig. 2 is a sectional view of the device taken in the plane 2--2 of Fig. 1.

Fig. 3 is a front view of the same.

Fig. 4 is an enlarged fragmentary view of the toothed end of the movable jaw and a rotary pawl illustrating the operation of the spring on the pawl cam.

Fig. 5 is a similar view of the toothed end of the movable jaw with a dog pivotally mounted to the movable handle illustrating the operation of the dog spring.

Figs. 6-1O are various fragmentary views illustrating in pairs, Fig. 6a to 10a respectively, the simultaneous position of the dog and pawl respectively in various movements of the handle.

My novel device comprises a hand-operated plier tool 10, using double lever to gain mechanical advantage. The movable handle 11, and the advancing dog 12, make up one lever. This lever acts upon a jaw lever 13 pivoted at 14, which is in effect the second lever. This results in a multiplication of the input force giving a much greater force at the jaws 15 and 15a, the latter jaw representing the stationary jaw.

Fired handle 16 with handle 11 are relatively long to obtain the necessary mechanical advantages. However, the tool has been devised so that it takes four short distance strokes of the movable handle to complete one full stroke of the movable jaw. This keeps the maximum spread between the ends of the handles about one fourth of the span expected of the usual pliers.

The movable jaw 15 is shown in Fig. 2 in closed posiice tion, having at its driven end a toothed portion provided with four teeth 17-20 respectively. The jaw 15 is pivoted at pin 14 to stationary jaw 15a which is recessed as at 21 to accommodate the toothed portion. A spring 22 connects the movable jaw to the fixed jaw and the jaw assembly of movable jaw, fixed jaw and spring are movable with respect to the body 23 by means of jaw adjuster 24, which comprises an eccentric shaft mounted in recess 25 of the body and extending into recess 26 of the fixed jaw. The shaft when rotated will slide the jaw assembly longitudinally with respect to the handles, the dog and other parts of the operating mechanism. This allows for an accurate adjustment to insure maximum engagement of teeth and dog despite slight variations resulting in their fabrication and assembly.

The jaw body 23 made of sheet metal is folded to form side wings 27 to accommodate the jaw assembly, the pivot pin 14 for the movable jaw being given sufficient clearance as at 28 to enable the jaw assembly to move therebetween. The sheet metal of the jaw body is extended to form the stationary U-shaped handle 16 which accommodates one leg of the spring 29 positioned between the handles to bias them to open position.

The pivot pin 30 of movable handle 11 extends through the wings 27 of the frame body, the latter of which supports as well a pivot pin 31 for a rotary pawl 32, herein described. A spring 33 is positioned between the dog and the pivot 30 of the movable handle for controlling the dog, which is pivoted to the handle at pivot pin 34.

One end of pawl spring 35 is riveted to the frame at 36, and operates on the cam 37 mounted to the shaft 30 of the rotary pawl.

The rotary pawl and the dog are positioned adjacent each to the other and operate sequentially on the teeth of the movable jaw as follows:

Figures 6 and 6a The movable jaw 15 is held in wide open position by the return spring 22. The movable handle 11 is also held in wide open position by the compressed spring 29. In these positions, constituting the starting position for the tool, the rotary pawl 32 is held up against the top of the first tooth 17 of the movable jaw by action of the pawl spring 35 on the cam 37 of the pawl. The connector 38 shown in the jaw is completely free at this stage.

Figures 7 and 711 Figures 8 and 8a These figures show the movable handle 11 returning to the open position after the completion of the first stroke. The advancing dog 12 is being deflected by the second tooth 18 of the movable jaw lever 13 as the handle 11 returns to the open position. When the handle arrives at the full open position the dog will snap down against the abutting surface on the movable handle, and the tip of the dog will be in place under the second tooth in the same relationship as it is to the first tooth in Fig. 6. Note, that although the movable handle is returning to the open position, the movable jaw does not move, being held in place by the rotary pawl under the first tooth. It is at this stage, after the first stroke, that the connector is gripped by the jaws, eliminating the need for a third hand to hold the connector in place.

Figures 9 and 9a These figures show the movable handle at the completion of the fourth stroke. The movable jaw has now travelled one full stroke and the indentation of the barrel 39 and the closing of the shroud 40 of the connector 38 has been completed. The pawl spring 35 acting on the cam 37 of the pawl 32 has swung the rotary pawl around,

and under the bottom of the last tooth 20 on the movable jaw lever 13.

Figures 10 and 10a These figures show the movable handle 11 returned to the full open position in which the dog swings out of the 'line of action of the teeth on the movable jaw 13 and the movable jaw returning to but not yet arrived at the full open position. This position illustrates how the movable jaw lever 13 pushes on one end 41 of the rotary pawl 32 swinging it around and bringing the other end 42 of the pawl spring into place, ready for operation in the next series of strokes. The pawl spring 35 allows the pawl to be rotated and only acts upon the sharp corner of the corresponding cam 37 of'the pawl as it is brought around into proper position. When the movable jaw returns to the full open position, brought there by the jaw lever return spring 23, it finally releases the installed connector which can now be removed from the tool.

In use the connector is placed in the jaws and pushed up against a stop surface 43 on the stationary jaw 15a. One stroke of the moving handle 11 will secure the connector 38 in this position, and the conductor cable can now be inserted in the connector without further handling of the connector itself.

In the foregoing I have provided a multiple-stroke plier which has a large mechanical advantage secured by long lever handles without the usual attendant disadvantage of a large lever and spread. The nose of the pliers-is small which allows the operator to insert the pliers into a restricted space containing the end of a cable and readily install a connector thereto. The spread of the handle ends being small, my pliers may be used by people with small hands, especially women. This reduced spread additionally prevents operator fatigue.

In my device the connector can be seated and secured in position prior to insertion of the conducting cable. This eliminates the need for three hands to make an installation.

The ratchet and rotary pawl prevent the jaws from opening until the jaws have been completely closed, thus insuring a complete and uniform indentation every time.

The jaws may be opened widely with a limited spread of the levers. This will permit connectors of increased size to be inserted into a plier of normal length.

The invention permits use of a double lever which greatly multiplies the input force to enable both indenting and shroud closing operations to be simultaneously accomplished without increasing the overall length or spread.

I have thus described my invention, but I desire it understood that it is not confined to the particular forms or uses shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of my invention, and, therefore, I claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which, objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to attain these objects and accomplish these results.

I claim:

1. A multiple stroke tool comprising a body, a pair of connected jaws mounted on said body, one of said jaws being movable with respect to the other jaw, a plurality of teeth on the movable jaw, a movable handle mounted on said body, a spring pressed dog connected to said movable handle and successively engaging said teeth to advance the movable jaw toward the other jaw upon repeated movement of the handle toward and away from the body, holding means mounted on said body and engaging successive teeth for supporting said movable jaw while said dog is disengaged upon movement of the handle away from said body, and means for releasing the hold ing means from said teeth and separating the jaws only after the holding means has engaged the last tooth.

2. The multiple stroke pliers of claim 1 wherein the holding means is provided with a plurality of operating surfaces, each capable of engaging successive teeth, and

means for changing from one operating surface to another after the holding means has engaged the last tooth.

3. The multiple stroke pliers of claim 1 wherein the holding means is provided with an integral shaft and a plurality of operating surfaces to permit rotating the holding means for alternately causing the operating surfaces to change positions after the holding means has engaged the last tooth, a cam positioned on said shaft, and a spring for biasing the cam and causing the holding means to rotate.

4. The multiple stroke pliers of claim 1 wherein means are provided on said body for adjusting the position of the jaws with respect to the body and associated parts.

5. The multiple stroke pliers of claim 1 wherein said movable jaw is pivotally connected to the other jaw, and adjustable locking means is provided for locking said other jaw to said body in one of a plurality of positions whereby the position of the jaws may be adjusted with respect thereto.

References Cited in the file of this patent UNITED STATES PATENTS 2,339,880 Romanoff Jan. 25, 1944 2,413,178 Feltman Dec. 24, 1946 2,643,564 Klein et al June 30, 1953 FOREIGN PATENTS 80,545 Sweden May 29, 1934 

